And the cable contracts provide basically guaranteed revenue as opposed to the risk of trying out online publishing. Execs want to cover their asses, not risk them. The potential payoff of going fully online is probably not high enough to justify risking their entire revenue base.

HBO is just a publisher, their expertise is sifting through and finding great creative talent to produce great shows. There's not a big difference between cable TV and internet, they share the same last mile, even. It just takes a long time for incumbents to adapt to change.